It's no coincidence that, once The Beatles became available on iTunes, music sales fared better.
Music sales in the United States were up 1.6 percent through May 8, according to Nielsen Soundscan. More than half of those sales went to digital retailers, as physical album sales continued to plummet.
Although Nielsen doesn't have specific sales figures for digital Beatles tracks, the patterns are pretty obvious. Sales of catalog music -- old stuff, that is -- shot up immediately in November, when The Beatles hit iTunes, and has continued to see year-over-year growth in every month since.